From: Matteo Facchinetti <matteo.facchinetti@sirius-es.it>
Date: Wed, 12 Jun 2013 07:21:42 +0000 (+0200)
Subject: serial/mpc52xx_uart: fix kernel panic when system reboot
X-Git-Tag: firefly_0821_release~176^2~5846^2~11
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8a29dfb8b67fbea03e084370d93fc99cbf375535;p=firefly-linux-kernel-4.4.55.git

serial/mpc52xx_uart: fix kernel panic when system reboot

This bug appear when a second PSC based driver appends an interrupt
routine to the FIFO controller shared interrupt (like spi-mpc512x-psc).
When reboot, uart_shutdown() remove the serial console interrupt handler
while spi-mpc512x-psc isr is still activate and cause the following kernel
panic:

The system is going down for reboot NOW!rpc (ttyPSC0) (Mon Jun 10 12:26:07 20
INIT: Sending processirq 40: nobody cared (try booting with the "irqpoll" option)
CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0-rc4-next-20130607-00001-ga0bceb3-dirty #5
Call Trace:
[cfff9f00] [c0007910] show_stack+0x48/0x150 (unreliable)
[cfff9f40] [c005ae60] __report_bad_irq.isra.6+0x34/0xe0
[cfff9f60] [c005b194] note_interrupt+0x214/0x26c
[cfff9f90] [c00590fc] handle_irq_event_percpu+0xd0/0x1bc
[cfff9fd0] [c005921c] handle_irq_event+0x34/0x54
[cfff9fe0] [c005b8f4] handle_level_irq+0x90/0xf4
[cfff9ff0] [c000cb98] call_handle_irq+0x18/0x28
[c050dd60] [c000575c] do_IRQ+0xcc/0x124
[c050dd90] [c000eb04] ret_from_except+0x0/0x14

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/serial/mpc52xx_uart.c b/drivers/tty/serial/mpc52xx_uart.c
index 9ba194590a80..e1280a20b7a2 100644
--- a/drivers/tty/serial/mpc52xx_uart.c
+++ b/drivers/tty/serial/mpc52xx_uart.c
@@ -1058,6 +1058,9 @@ mpc52xx_uart_shutdown(struct uart_port *port)
 	if (psc_ops->clock)
 		psc_ops->clock(port, 0);
 
+	/* Disable interrupt */
+	psc_ops->cw_disable_ints(port);
+
 	/* Release interrupt */
 	free_irq(port->irq, port);
 }